1. Field of the Invention
The present invention relates to a communication repeater that wirelessly transmits and receives a communication signal.
2. Description of the Related Art
A mobile communication device such as a mobile phone and Personal Handy-phone System (PHS) performs communication with other communication devices by receiving a communication signal output from a base station directly or via a communication repeater. As for a method of communication performed by a mobile communication device, performing communication with power-line carrier communication is proposed (see, for example, Japanese Patent Application Publication Laid-Open No. 2003-169004).
The communication repeater can perform communication with communication devices within a certain area by wirelessly transmitting and receiving a communication signal. However, even if the physical distance is close, there may be areas with which the communication repeater cannot perform communication, for example, the underground of a building where there are many objects (such as walls and floors) that block or attenuate a communication wave.
Japanese Patent Application Publication Laid-Open No. 2003-169004 describes how a mobile communication device performs power-line carrier communication by using a charging stand, but fails to describe any apparatus that is caused to transmit a communication signal of the power-line carrier communication. Moreover, a communication signal superimposed on a power line cannot maintain its signal components after passing through a substation directly. Thus, it becomes necessary to install facilities such as providing equipment to bypass a communication signal for each substation to ensure communication in a wider area with power-line carrier communication.